Color-stable molasses



Patented Apr. 6, 1943 COLOR-STABLE Momssss Charles J. Krister, Cleveland, Ohio, assignor to E. I. du Pont de Nemours & Company, Wilmington, DeL, a corporation of Delaware No Drawing. Application January 23, 1940, Serial No. 315,163

4 Claims.

This invention relates to processes for retarding an increase in the color of molasses, and more particularly to processes wherein such a color increase in molasses is retarded by adding to the molasses a small amount of a reductant selected from the group consisting of formic acid, urea, thiourea, benzalde'hyde, benzene phosphonic acid, sodium thiosulfate and alpha-naphthol.

Molasses when freshly made ordinarily has.a much lighter color than after it has stood for a time. This increase in the color of molasses upon storage presents a serious difficulty when the molasses is used as a raw material in the manufacture of certain chemical products such as lactic acid because the color tends to carry over into the chemical product and render it less salable. A light-colored grade of lactic acid, for instance, commands a better price than does a darkcolored grade of equal acid content. Heretofore it has been the practice to remove objectionable colored matter during the course of manufacture of the chemical product, but such purification steps are expensive, adding appreciably to the ultimate cost of the product.

Difficulties due to the coloring of molasses during the manufacture of chemical products therefrom could be minimized by using only freshly prepared molasses. However, the manufacture of molasses and the manufacture of chemical products from molasses are ordinarily carried on at widely separated geographical locations, hence it is not always feasible to use fresh molasses since some time is required for shipment from the point of manufacture to the point of use. Moreover, the production of molasses is a seasonable operation, whereas the manufacture of chemicals therefrom is ordinarily continuous. Under present commercial practice, therefore, the storage of the molasses for considerable periods frequently is found desirable. The prevention or retardation of the development of color in the molasses during storage thus becomes a problem of commercial importance.

Now I have found that the increase in .the color of molasses which ordinarily takes place during storage may be substantially retarded by adding to the molasses a small amount of a reductant selected from the group consisting of formic acid, urea, thiourea, benzaldehyde, benzene phosphonic acid, sodium thiosulfate and alpha-naphthol.

By the processes of my invention an increase in the color of molasses may be retarded to such an extent that even during a considerable period of standing the increase in color is relatively small. The color-stable molasses so produced is ideally adapted for use as a raw material from which to manufacture chemical products since it may be stored for long periods without excessive coloration and may therefore be used with a minimum of difficulties due to carry-over of color constitutents into the chemical products.

The nature of my novel processes for stabilizing the color of molasses and of the color-stable molasses produced may be better understood by reference to the following illustrative examples.

Example 1 The color of a. lot of freshly prepared Cuban invert molasses containing 84.3 per cent total invert sugar and 36.9 per cent reducing sugar was determined by diluting a sample of the molasses to one hundred times its volume with water and. comparing the color of the diluted.

sample with a permanent color standard. The sample wasfound to have a light amber color.

To another portion of this molasses there was then added 0.5 per cent by weight of a reductant, namely, formic acid. The treated molasses was then allowed to stand under ordinary conditions of storage. After storage for one year the color of the treated molasses was again determined by the above-described dilution method and found to be unchanged, that is, it was still a light amber color. The color of a sample of the same molasses which had been stored under identical conditions for one year without the addition of any reductant was also determined and found to be a dark brown color, thus "indicating that the reductant in the treated sample had prevented an increase in color which would have otherwise occurred.

The use of another reductant, sodium thiosulfate, for retarding the increase in color of molasses in accordance with a process of my invention is shown in Example 2.

Example 2 The color of a lot of Cuban molasses was determined as in Example 1 by dilution and found to be a light amber. To the molasses there was then added 0.5 per cent by weight of the reductant, namely, sodium thiosulfate. After storage for one year it was found that this treated molasses had not increased in color as determined by the dilution test, whereas the sample of the original molasses to which no reductant had been added showed a substantial color increase after one year of storage under identical conditions.

Following the conditions of Example 2, there was added to separate lots of molasses 0.5 per cent by weight of each of the following reductincrease when the reductants were present and increased substantially when no reductant was present.

The amount of a reductant required to prevent the increase in color of molasses according to a process of my invention is a very minor proportion of the total weight of the molasses. For best results the amount of the reductant should ordinarily be not less than about 0.1 per cent of the total weight of molasses. On the other hand, more reductant than about 2 per cent of the weight of the molasses is ordinarily not required. Larger amounts than about 2 per cent may sometimes interfere in the subsequent use of the molasses for manufacturing chemical products.

While in the above examples I have shown that the processes of my invention are particularly applicable to the prevention of an increase in the color of molasses, it will be understood that these processes may likewise be used for preventing a color increase during storage in related products such as sorghum and other concentrated juices of natural products from which the sugar cannot be crystallized. The term molasses is used herein in its ordinary meaning to cover the fixed, dark-colored vlscid syrup which drains from sugar in the process of manufacture.

While I have shown specific embodiments of Q the processes and products 01' my invention, it

will be understood that various modifications and equivalents may be employed without departing from the scope of my invention.

I claim:

1. In a process in which a light-colored molasses istreated to retard the development 01 color therein during a storage period, the steps comprising adding to the molasses and maintaining therein during the storage period a reductant selected from the group consisting of formic acid, urea, thiourea, benzaldehyde, benzene phosphonic acid, sodium thiosulfate, and alpha-naphthol, the amount of reductant added being a small but effective amount and being a minor portion of the total weight of the molasses.

2. In a process in which light-colored molasses is treated to retard the development of color therein during a storage period, the steps comprising adding to the molasses and maintaining therein during the storage period from about one-tenth to two per cent of a reductant selected from the'group consisting of formic acid, urea, thiourea, benzaldehyde, benzene phosphonic acid, sodium thiosulfate, and alpha-naphtho].

3. A color-stable molasses containing a small but effective amount of a reductant selected from the group consisting of formic acid, urea, thiourea, benzaldehyde, benzene phosphonic acid, sodium thiosulfate, and alpha naphthol, the amount of reductant being a minor proportion of the total weight of the molasses.

4. A color-stable molasses containing from about one-tenth to two per cent of a reductant selected from the group consisting of formic acid, urea, thiourea, benzaldehyde, benzene phosphonic acid, sodium thiosulfate, and alpha-naphthol.

' CHARLES J. ImISTER. 

